The present invention relates to a solid-state image sensor and, more particularly, to a MOS-type solid-state image sensor including pixel units each having a signal amplification function.
MOS-type solid-state image sensors have recently received a great deal of attention because of the following advantages. A MOS-type solid-state image sensor allows a reduction in size, can be driven by a single power supply, and allows all components such as an image sensing section and peripheral circuits to be integrated into one integrated circuit chip by a MOS process.
The MOS-type solid-state image sensor suffers the problem of leakage of electrons into adjacent pixel units upon incidence of long-wavelength light and the problem of expansion of the depletion layer of a photodiode with a reduction in pixel unit size. These problems will be described below.